Molecular dynamic simulation of tool groove wear in nanoscale cutting of silicon

Abstract

Tool wear is one of the bottlenecks that decrease the machinability of hard and brittle materials in single point diamond turning (SPDT). Specifically, a microgroove generated on the cutting edge is an important character of tool wear, which leads to the formation of subcutting edges and facilitates the ductile to brittle transition in machining. However, the mechanism of the groove wear influence on the machined workpiece, especially the subsurface damage, is not clear just by the experimental investigations. In this paper, molecular dynamic simulations were carried out to explore the influence of groove wear on workpiece subsurface damage in SPDT of single crystal silicon. The propagation of grooves was also investigated by discussion of the stress and temperature distribution on the cutting edge. The Weierstrass-Mandelbrot function was adopted to set up groove wear on the tool flank face. It is concluded that grooves improve the atomic flowing ability and the plastic deformation in the workpiece. Moreover, the grooves can also cause polycrystal transition in the workpiece subsurface. The thickness of the subsurface damaged region is increased when groove wear becomes severe. This study contributes to the understanding of the details involved in the interaction between tool groove wear and workpiece, which is advantageous to improve the machined surface quality.

Simulation of gallium phosphide cutting mechanism in ductile regime using molecular dynamics

“…In their study a correlation between the stagnation zone shape and the tool cutting edge radius was described. Liu et al [28] have observed subsurface damage during the CMDS of the silicon cutting mechanism. However, the subsurface damage was detected as non-identifiable structures in the silicon crystal and were parallel to the shear plane.…”

Nanometric cutting: Mechanisms, practices and future perspectives

“…MD studies reveal the thermo-chemical mechanism is due to the reduction in the cohesion energy of carbon under the high cutting temperature [13], as well as the graphitization of diamond lattice [125]. The formation of SiC hard particle from the dangling bonds at the tool flank face is considered as another source of abrasive wear during the nanometric cutting of Si [179], and the induced groove on flank face increases the subsurface damaged region and promotes the formation of polycrystalline structure [180]. Similar wear patterns are also observed in the machining of SiC (Figure 13d), while the cutting length the tool edge can sustain is only tens of metres due to the great hardness of the workpiece [181].…”

Molecular Dynamics Simulation of Nanomachining Mechanism between Monocrystalline and Polycrystalline Silicon Carbide

“…[17][18][19][20] On the premise of an accurate modeling, the results will show good agreement with that by experimental method according to the reasonable potential function selection. As an example, Liu et al [21] conducted MD simulations to explore the effect of groove wear on the subsurface damage of monocrystalline silicon during the diamond cutting process, and the expansion of the groove was also studied by considering the temperature and stress distribution on the tool edge. Mylvaganam et al [22] applied MD method to research the scratch-induced deformation in monocrystalline silicon; they found that the dominant mechanisms are amorphous phase transformation and nano-twins.…”